42 ZOOPHYTES. 



branchia-like organs. In figure 3b, they are seen in profile in their 

 natural position (c' to d'), and in the vertical view in 3d, one appears 

 either side of each lamella ; this is shown still more distinct in 

 figure 3e. These organs are enlarged in figure 3f. They are 

 transparent, and are transversely divided into narrow compartments, 

 each about owo of an inch in breadth. The margin is crenated, corre- 

 sponding with the compartments. Each compartment, as is more 

 distinctly exhibited in figure 3^, is traversed along its middle by a 

 distinct vessel, which terminates in a small process on the margin. 

 Vibratile cilia were apparent on these organs, as is represented in 

 figure 3g, and they were observed to continue in motion for an hour 

 after separation from the animal. These cilia were about ^cuo of an 

 inch in length. 



The two organs of each pair were united to a common duct, 

 which, in the specimen examined, had a bluish colour, as shown in 

 figure 3/"; and by this duct they were attached to the margin of the 

 lamella — one being situated either side — and thus their surfaces were 

 free to be bathed by the water with which the animal distends itself 



35. The structure of these organs is such that we can hardly doubt 

 their branchial nature : yet no circulating fluid was detected within 

 them. Lesueur, who observed them in his excellent dissections of 

 West India species, calls them arcuated organs, and supposes them to 

 " perform the functions of the liver."* 



The modes of nutrition in the Zoanthidse, are the same as in the 

 Actinia. 



The Tiibipora. 



36. The structure of the Tubipora has been illustrated by Quoy 

 and Gaymard, in the voyages of the Uranie and Astrolabe. The dis- 

 sections made by the author confirm in general their observations, yet 

 diff'er in some points of interest. 



The Tubipora is a cylindrical animal, expanding above a star of 

 eight tentacles. The animals are often of a lilac or rose tint, and 

 grow in large clusters; and, as they appear beneath the water about 

 the reefs, they are as perfect beds of pinks as those of our gardens. 

 Figure 1, on plate 59, represents some of these polyps of the natural 

 size; and figures \a and 2, two individuals of the same genus enlarged. 

 The eight tentacles are fringed on either side by small papillae, each 

 of which has a minute puncture at apex. Both the papillae and the 



* Jour. Acad. Nat. Sci., Philad., i. 183, 184, 185, and plate viii., fig's. 1, 5, 9. 



